1. Field of the Invention
The present invention relates to an easy-to-start structure of a D.C. brushless motor in which the rotor of the motor may rest in an easy-to-start position when the rotor stops rotating.
2. Description of the Related Art
FIG. 9 of the drawings, which corresponds to FIG. 2b of U.S. Pat. No. 4,899,075 to Hasebe issued on Feb. 6, 1990, illustrates a conventional stator structure of a bi-directional brushless D.C. motor comprising a pair of stator cores each having a plurality of salient poles 9axcx9c9d each of which is shaped to have a notched portion 92 in one of opposite corners, in a direction of rotation of the rotor, and oriented so as to be next to the unnotched corner of the stator pole adjacent thereto.
FIG. 10 of the drawings illustrates another conventional stator structure of a D.C. brushless motor structure disclosed in Taiwan Utility Model Application No. 81217854 published on Nov. 1, 1993 and entitled IMPROVED STATOR YOKE FOR A STATOR OF A HEAT-DISSIPATING FAN MOTOR. Each of an upper stator yoke 8 and a lower stator yoke 8 comprises plural poles 81 on a peripheral edge thereof, each pole 81 having a notched portion 82 in a side thereof.
The notched portions 92 and 82 in these conventional D.C. brushless motor structures are designed to create an uneven magnetic force associated with the permanent magnet, thereby preventing the rotor from stopping in a dead corner for starting and thereby allowing the rotor to be restarted.
An object of the present invention is to provide an easy-to-start structure of a D.C. brushless motor that prevents the rotor of the motor from stopping in a dead corner for starting and that allows the rotor to be restarted easily.
An easy-to-start structure for a D.C. brushless motor in accordance with the present invention comprises a base including a through-hole having an end in which a support section is provided. Plural windings and an IC control member are mounted to the base, the IC control member being located between two windings that are adjacent to each other. At least one magnetically attractive positioning member is mounted to the base and located in a space defined between two windings that are adjacent to each other. A rotor comprises a shaft rotatably held by the support section and a permanent ring magnet mounted to the shaft, the permanent ring magnet having north and south poles, each of the south pole and the north pole having a strong magnetic area. The positioning member attracts, directly aligns with, and thus retains one of the strong magnetic areas of the permanent mg magnet in a position proximal to the positioning member when the rotor stops. Thus, the rotor rests in a predetermined position not located in a dead corner for restarting.
Other objects, specific advantages, and novel features of the invention will become more apparent from the following detailed description and preferable embodiments when taken in conjunction with the accompanying drawings.